Determination of silicon dioxide in niobium-enriched slag by perchloric acid dehydration-gravimetry combined with inductively coupled plasma atomic emission spectrometry
LIU Chun1,2, WANG Dan1,2, ZHANG Yi-ming1,2,GUO Yu1,2
1. Ruike National Engineering Research Centre of Rare Earth Metallurgy and Function Materials Co., Ltd., Baotou 014030, China; 2. Baotou Research Institute of Rare Earths, Baotou 014030, China
Abstract：After the sample was fused by Na2CO3-NaOH at 750 ℃ and acidified by HCl, it was treated by perchloric acid smoking to make silicic acid dehydrate into silicon dioxide colloid. The obtained sample was filtered and washed, and the precipitate was then burned to reach constant weight at 950 ℃. After silicon in the precipitate was volatized by hydrofluoric acid in the medium of sulfuric acid, the precipitate was burned again to constant weight. The difference of the two weight results were the amount of silicon dioxide in the precipitate. While the silicon dioxide left in the filtrate was determined by inductively coupled plasma emission spectrometry (ICP-AES). The total amount of silicon dioxide in the niobium-enriched slag sample was thus obtained by adding the two results. It indicated that, after the precipitate reached constant weight, there was a large amount of niobium compound left which, however, its influence on the determination could be ignored by silicon volatilizing. The proposed method was applied to determination of silicon dioxide in niobium-enriched slag, the results were consistent with that by ICP-AES. The relative standard deviation (RSD,n=10) was 0.48%, and the standard addition recovery was 99%-100%.
YU Hong-hao, XUE Xiang-xin. Preparation of precipitated silica powder from iron ore tailing[J]. The Chinese Journal of Process Engineering, 2008, 8(2): 300-304.
